Good news for those who love local oysters and clams: the state Department of Health says there’s been a steady improvement in water quality for nearly a decade, leading to fewer closures of shellfish beds in Puget Sound.

The key measure is of fecal coliform bacteria, which lives in human and animal waste. Runoff from farms and leaky sewage systems carries the bacteria and contaminates shellfish beds. People who eat the polluted shellfish can get sick.

We’re still dealing with landslides and flooding from the heavy rains brought by last week’s Pineapple Express storms. But the downpour also washed a flood of gunk and junk off of the region’s streets, sidewalks and parking lots, into more than 4,500 storm drains and right into Puget Sound.

Storm drains usually empty underwater, so nobody sees the flood of crud that pours into rivers and bays across the region.